Tim Gay’s The Physics of Football segments appear on NFL Blast, which airs on television in 194 countries, but not in the United States.

Tackling Physics

By Rhonda Hillbery

A cherry picker rises high in the sky. A bowling ball is dropped in slow-motion onto a layer of bricks. The bricks are crushed. This may sound like a stunt on late-night television, but it’s not. It’s a physics lesson.

“This is an incredible amount of force, almost one ton,” says our instructor, Tim Gay ’75, a University of Nebraska, Lincoln, professor of physics. Wearing his signature bow tie and wire-rimmed glasses, Gay goes on to explain how the force of a National Football League “hit” is comparable to dropping a bowling ball from a height of 130 feet. Behind him looms a chalkboard with an equation scribbled across it: F = ma, Newton’s Second Law governing the relationship between force and acceleration.

We learn that in football, the external forces are better known as the defense, and Newton’s law allows the calculation of just how much force applies. Gay shows that a big NFL hit, with the offense and defense both moving about 10 meters a second, adds up to about 9,000 newtons of force.

“It gives both players an acceleration of 10 times that of gravity. So the next time you see [a linebacker] make somebody pay, keep in mind just how high the price really is. For The Physics of Football, I’m Dr. Tim Gay.”

Gay, who is well known as the “football physicist”
among Husker fans, appears in a caricature by Dan Claes,
fellow University of Nebraska physics professor.

Most American football fans have never heard of Gay. His two-to-four---minute segments appear on a magazine show called NFL Blast. Curiously, it airs on television in 194 countries, including Fox Eastern Europe in Azerbaijan and ESPN Star Sports in Cambodia, but not in the United States. Each show covers the week’s NFL action, with player profiles, music videos—and football physics.

“It’s basically a propaganda tool of the NFL to convert the heathens to the true American game,” jokes Gay, who seems to take his growing celebrity none too seriously and works the same droll sensibility into each of his segments. What he does take seriously is his love for football, and the opportunity to teach physics to a class of millions. And it turns out that football’s spirals, spins, punts, and fumbles provide an ideal laboratory to explore the laws of Newtonian mechanics.

Managing to look authoritative and credible without seeming stuffy, Gay performs his stand-ups, as they are called, in a deliberately old-fashioned-looking classroom location near the exurban Philadelphia headquarters of NFL Films.

In one of the segments filmed there, the bearded, six-foot-four Gay, who played football his freshman and senior years at Caltech, launches into an explanation of why players run faster
on artificial turf than grass. It’s not merely because of the players’ athletic might or the inherent smoothness of turf. Some understanding of physics is required.

“On every NFL Sunday, there are two very different games being played: games on grass and games on turf. The type of field has a major impact on the speed at which players run, and speed is one of the most important factors in professional football.”

As we hear Gay explain over a montage of quick-paced football action supplied from the NFL’s vast vault of images, artificial turf allows a greater percentage of player energy to go toward running speed. Grass absorbs more of the energy of running feet. This is because turf has a higher “coefficient of restitution” than grass.

If one of society’s greatest challenges is making science interesting to people who find it boring or intimidating, maybe Gay has hit on something fundamental.

“My attitude is, if I can get one kid interested in physics and going to Caltech as a result of doing this, it’s all worth it. That’s my goal.” Even a few of his football-playing students have become ardent physics fans, in large part due to his hands-on approach.

Here’s the football physicist dissecting the fumble, using the concept of torque: “The history of the NFL is strewn with examples of a single fumble helping to decide the outcome of the game,” Gay says, as a series of slow-motion gridiron gaffes flit by on screen. In an endless effort to prevent fumbling, coaches drill ballcarriers in the “four-point method” of securing the ball. That is, anchoring it at both ends between the fingers and against the torso, as well as securing it against the torso and inside the arm.

“The application of force on an object tries to make it rotate about an axis perpendicular to that force. The measure of that force is called torque.”

The player trying to dislodge the football supplies the force, and the ball- carrier’s goal is to supply enough countertorque to keep the ball in place. “So the next time your favorite player drops the ball, don’t scream for him to be traded. He just forgot to do his physics homework. For The Physics of Football, I’m Dr. Tim Gay.”

A fan might well wonder, why sully the sanctity of football with science? Because it turns out that fans like it, says NFL Films producer Brad Minerd, who you could say quarterbacks Gay’s NFL Film appearances. He points to the success of Gay’s first season on NFL Films as clear evidence that sports fans do have an appetite for learning how mass, velocity, and force affect the dynamics of the prolate spheroid otherwise known as a football.

The Physics of Football is intended to be educational, but with a difference. “We wanted something different from coaches marking X’s and O’s on a chalkboard, ” Minerd says. “Tim is excellent at taking complicated scientific principles and making them very digestible.

At first Minerd’s colleagues and bosses weren’t sure, he admits. “Maybe they didn’t think the science behind football was that interesting. I knew it was very important that we have the right person.” To illustrate the physics concepts that ultimately wind up on Gay’s segments, Minerd says he plows through thousands of hours of NFL play that capture every game played since 1963. In one such segment, players explode in motion at the kickoff, as Gay explains how in the first second of game play, the teams will expend enough combined energy to lift a pickup truck 10 yards in the air.

Minerd says Gay’s intense curiosity serves him well on and off the screen. “Dr. Gay is knowledgeable and passionate about the subject” and “really great at giving me the material that I need to turn it into a TV program. Say I am thinking of doing a segment on human reaction time, I can just call him up on the phone and say, ‘Give me a good metaphor, something regular people could relate to. Is 0.2 seconds the amount of time it takes a person to snap their fingers? Is it the length of a heartbeat?’ You can throw out ideas like this and he’s busy working out calculations in the interest of coming up with an answer.”

Gay likes to point out that while at Caltech, he played tackle on a football squad so notoriously inept that it was profiled by the Wall Street Journal with the headline “Cal Tech’s [sic] Beavers Play Up to Potential--—Which Isn’t Much.” The school eventually dropped intercollegiate football but continued with “club” play through 1993, after which the football program officially vanished from
campus.

Gay had better luck with physics, earning his PhD in experimental atomic physics at the University of Chicago in 1980. He worked as a research physicist and lecturer at Yale until 1983, when he joined the faculty of the University of Missouri–Rolla and then moved to the University of Nebraska in 1993.

At Nebraska, he heads a research group focused on the scattering of polarized electrons by atomic and molecular targets. He also makes time to be the Cornhusker football “team physicist,” getting involved with the development of exercises in the weight room, and the analysis of football aerodynamics. He has even worked to recruit players, including a current six-four 300-pound offensive tackle majoring in physics.

It was Jeff Schmahl, director of Nebraska’s HuskerVision program,
who came up with the idea of throwing a little science at the Lincoln football crowd. Earlier on, he had helped

Nebraska become one of the first schools in the country to put up a big screen to entertain fans during the TV timeout periods.

After analyzing several departments and curricula on campus, Schmahl concluded that physics could provide a natural link between football and the educational mission of the university. As Gay tells the story, Schmahl then sent an undergraduate broadcasting major over to the physics department main office to inquire whether “there were any physics professors who loved football and were shameless self-promoters. In unison, the secretaries answered ‘Tim Gay.’”

The rest is Cornhusker history. For the past four years during breaks from the action, 76,000 fans in a sold-out stadium have seen Gay go to great lengths to illuminate physics. Once he even lay down on a bed of nails to demonstrate the concept of distribution of force. He used this swami-like posture to illustrate how a football helmet helps distribute the force of a hit over a
larger area, thereby reducing the odds of serious head injuries to players.

Word of this new addition to the Husker lineup began to get out in midseason 1999 when ABC World News Tonight with Peter Jennings headed out to Lincoln and picked up the story. Then People magazine wrote about Gay, and his name found its way to Minerd, who had been scouting around for someone to impart the science behind football to a general audience. Tim Gay was one of several possible hosts asked to apply.

He quickly got the job.

After one season, NFL Films partners around the globe are enthusiastic about seeing more of Dr. Gay, Minerd says. NFL Films expects to produce a series of new segments for Blast next year. But there’s more. Encouraged by The Physics of Football’s success to date, Minerd says that NFL Films hopes to produce a full-length program for U.S. audiences.

Minerd says Gay has proved himself unflappable in front of the camera. He recalls how during one of the final takes on a very long, hot day of shooting, a piece of equipment crashed loudly on the set. Gay didn’t bat an eye. He continued speaking, says Minerd, refusing to let the interruption interfere with his delivery.

Schmahl too, has no doubt that Gay will travel well. The Nebraska show has been going strong for four years, he says, and is expected to produce original episodes for a new season. “Tim definitely has a great gift of communicating a lesson in about 60 seconds. Fans really enjoy him, and the stadium gets almost eerily quiet during his segments.

“One measurable thing we can see is people’s reactions. Are they watching? Just to gauge, you can tell when Football Physics is on up there. Ninety-five percent of the fans are paying attention.”

As for Gay, he is currently back in his Nebraska classroom, teaching modern physics and dreaming up new ways to tie the discipline to the real world, at least the part of it that concerns football. “I get to teach the biggest physics class in world history, and I don’t have to grade any homework.”